This study proposes to examine the neurodevelopmental effects of HIV infection in a large and stable population of infants in Uganda. It will extend a follow-up study of HIV positive newborns that is ongoing in Uganda. We will assess the cognitive, development, and neurologic status from birth to 24 months of 320 Ugandan infants who are HIV positive at birth and 100 infants who are HIV negative at birth. Specific aims are (1) a prospective assessment of the neurodevelopmental consequences of HIV infection (birth to 24 months) using measures of cognitive development (Bayley Scale and Fagan Test of Infant Intelligence), language development, neurologic status, and behavior; (2) identification of the factors which predict cognitive and neurologic deterioration in HIV infected infants; (3) detailed assessment of potential covarying influences including maternal health, family environment, and child nutrition status. The following propositions will be examined: (1) HIV infection will be associated with deterioration in neurodevelopmental status that is not accounted for by covarying factors; (2) Children's visual recognition performance at three months of age will predict subsequent developmental and neurologic status. Neurologic exam and the Bayley Scale will be given at three month intervals for the first 12 months and repeated at 18 and 24 months. Home visits to study subjects will be made every two weeks for the first six months of life and monthly, thereafter, until age two. The proposed study will enhance knowledge of the neurodevelopmental consequences of HIV infection in infants and young children, generate new information concerning factors that influence cognitive and neurologic outcomes, and test the utility of visual recognition performance for early detection of cognitive and neurologic deterioration in HIV infected infants.